I actually talked my wife into having a discussion about some of the things that have been "bothering me". I went with the (ridiculous) scripture the whole "new light" crap comes from. I had her read the whole chapter in Proverbs and then tell me what she thought it was about. Thankfully she played along. She saw the obvious point that it was just contrasting a righteous person and a wicked person.
I then pointed out that this is the chapter where they get the teaching about "new light". She looked puzzled. I then pointed out the verse. She saw my point but said she would do some research.
I then said I have a problem with all the failed prophesies. Then I showed her that scripture in Deut. about how to determine a false prophet. She said, "Well you have something there, I have to admit it." Again, though she said she would do more research.
So that was my 5 minute episode (prob more like 15). My take on it is this. The stimulus of doubt probably can't come from outside the person. I think I planted some seeds, but nothing earth shattering.
It takes a person months of "studying" to become one. It takes at least that long to un-become one, I would say.